by gingkoseto » May 31st, '10, 11:40
Unfortunately, most people who write about it don't have direct tea cultivation experience (including me). So what I say is only what I heard from farmers and professionals, and it's only one-side story.
From what I've learned, currently the most popular insecticide is pyrethroid type, (which is somewhat similar to household insecticide for mosques and cockroaches), such as valerate and cyhalothrin. They are decomposed relatively faster and when used in small amount, leave relatively smaller amount of residues.
What are not allowed to used for tea include Kalthane and Mathamidophos. Kelthane is widely used in developed nations including US and Canada, for fruits such as apples, peaches and grapes. I did some internet search on Kelthane. Kelthane leaves relatively higher DDT residue than most other legal pesticides. But since it's still allowed in developed nations, I assume all these countries believe the pesticide residue can be minimized through guidelines and regulations. Another example of pesticide not allowed for tea but allowed for other agricultural products is Methamidophos. It was banned on tea, vegetables and fruits in 2001 throughout China (most other countries in the world banned it for fruits and vegetables too). But it is being used for crops in many countries in the world, including developed nations such as US and Canada. In terms of the concerns of Kelthane, Methamidophos and some other highly dangerous pesticide, tea products are no less safe than fruits, vegetables and crops.
Application of fertilizer largely depends on the soil conditions. Many farmers believe it's easier to use organic fertilizer (many of them already use a lot of it because it contributes to tea quality) than using organic pesticide (which is very often unaffordable). But something to notice is, "organic" in farmers' mind is not always consistent with organic regulation. For example, in order to obtain organic certification (national or international), the farmer can only use sterilized (usually by high temperature) feces/urine but not the raw material. Other options (such as composting and buying industrial organic fertilizer) are costly. This makes organic fertilization very expensive too. Unless for certification purpose, people think it's an odd idea to treat feces before applying it. This is one of the many reasons that most Chinese tea farmers are not interested in obtaining organic certification.
As for Yunnan, there are a lot of wild or semi-wild tea trees in Yunnan, and they are pretty much organic. A Taiwan tea professional, Shi Kunmu, once said, "All the tea from Yunnan, as long as not treated artificially, is great tea." But nowadays people want more tea from Yunnan. In order to cultivate more tea, artificial pesticide and fertilizer must be used in a lot of plantations.
, I forget which book that was, hmmmm 
) not that I am scared of that kind of thing (I know it most likely is something similar to that...) at all if it is that, I LOVE the taste of puerh and know where food and stuff comes from... grew up around farms throughout my youth, but I am just curious... Clearly there is some organic and I know that's a whole other story, i am inquiring more about like the average farmer.
). But still there is a lot to explore on how to improve the systematic regulation of pesticide and fertilization, and how to make organic cultivation less costly and more profitable.
Please do send them all to me, I will pay for the shipping cost.